1. Field of the Invention
This invention relates to a connector for a ribbon cable and, more particularly, to a connector for coupling electrically conductive wires of a ribbon cable to traces of a printed circuit board and to a method of using such connector.
2. Description of the Prior Art
The development of new electrical cables in which a large number of wires are encapsulated in a flat insulating web has produced significant advantages in computers, telecommunication devices, and the electronic industry generally. These cables are manufactured with conductors formed as fine parallel wires, as small as 0.030 inches in diameter, located on closely spaced centerlines. They may be used for transmitting electrical power or, in the alternative, electrical signals.
Along with the obvious advantages of size reduction and ease of handling the flat cables per se, such flat cables also present certain disadvantages, both mechanically and electrically. From the mechanical standpoint, the fineness of the wires and the closeness of their spacing generally increase wire handling difficulties during the coupling of the individual wires to other electrical components. as connectors. Further, since their centerline spacings are usually small, they may not necessarily coincide with the standard centerline spacings for commonly used electrical elements thus creating interconnection problems. The development of even smaller cables with finer, more closely spaced wires, further aggravates these mechanical problems in addition to complicating the design of connectors compatible with such further miniaturized cables.
From the electrical standpoint, particularly when flat cables are used for signal transmission purposes, the closeness of wire centerlines dictates their positioning at a specific, precise, constant distance for a particular application if the accurate transmission of signals is to be accomplished. Of equal importance, when flat, multi-wire cables are terminated with connectors, such connectors must be designed for controlling the characteristic impedance of the transmitted signals while matching it to the cable as well as the electronic devices being coupled.
The prior art discloses many types of connectors for coupling ribbon cables to a mating connector and electronic device. Note, for example, U.S. Pat. Nos. 4,094,566 to Dola et al; 4,181,384 also to Dola et al; and 4,367,909 to Shatto et al. None, however, discloses a connector or method of use having sufficient utility for its convenient use with ribbon cables formed with conductive wires of 0.008 inches in diameter, several times smaller than those previously employed, cables with wires of a diameter as contemplated by the present invention. Such significantly reduced wire diameters will allow for the proportionate reduction in the spacing between centerlines to 0.0125 inches along with a proportionate increase in the number of wires per cable to 81 wires per linear inch. While U.S. Pat. No. 4,616,893 discloses a connector with controlled characteristic impedance between printed circuit boards, there is no prior art teaching or suggestion of releasable connectors for flat, multi-wire, signal transmission cables with controlled impedance characteristics matching the cable, the mating connector and the electronic devices to be coupled. Lastly, U.S. patent application Ser. No. 661,774 filed Oct. 17, 1984 in the name of Schwalm discloses the soldering of closely spaced wires as of a ribbon cable to connectors. Such disclosure, however, does not teach or suggest the present inventive method and apparatus for coupling ribbon cable wires to the connectors as contemplated herein.
None of these prior art patents teaches or suggests the accurate, efficient, convenient, and economical connector and method as described herein. Known methods and connectors are simply lacking in one regard or another.
As illustrated by the great number of prior patents, efforts are continuously being made in an attempt to more efficiently connect electrical elements of ever decreasing size. None of these prior art efforts, however, suggests the present inventive combination of method steps and component elements arranged and configured for coupling electrical elements as disclosed and claimed herein. Prior methods and connectors do not provide the benefits attendant with the connector and method of the present invention. The present invention achieves its purpose, objectives and advantages over the prior art methods and devices through a new, useful and unobvious combination of method steps and component elements, through the use of a minimum number of functioning parts, at a reduction in cost to manufacture and operate, and through the utilization of only readily available materials and conventional components.
These objects and advantages should be construed as merely illustrative of some of the more prominent features and applications of the present invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and advantages as well as a fuller understanding of the invention may be had by referring to the summary and detailed description of the preferred embodiment of the invention in addition to the scope of the invention as defined by the claims taken in conjunction with the accompanying drawings.